消化系统颗粒细胞瘤的研究进展

Recent Advances in Research on Granular Cell Tumor in Digestive Tract

消化系统颗粒细胞瘤在临床上非常少见,是一种来源于黏膜下层、具有雪旺细胞分化特征的神经源性肿瘤,生长缓慢,一般为孤立性结节,形态不规则,显微镜下瘤细胞呈巢状及索状排列,免疫组化显示神经特异性标记S-100蛋白表达阳性,恶性瘤细胞显著异型性。消化系统颗粒细胞瘤多无临床症状,常在内镜检查时发现,表现为灰白色或淡黄色黏膜下半球形结节,表面光滑,内镜下深挖或大块活检可提高病理诊断的准确率,超声内镜检查可显示肿瘤起源层次及扩散范围。通常认为有无转移、手术切除后是否复发是良恶性颗粒细胞瘤鉴别的主要标准。对直径<20mm的颗粒细胞瘤,首选内镜下局部微创切除治疗,对多发或来源于肌层的颗粒细胞瘤及恶性颗粒细胞瘤主要治疗手段为手术切除,放、化疗目前研究很少。消化系统颗粒细胞瘤治疗后复发率较高,恶性颗粒细胞瘤术后局部复发率达32%～59%,并可发生远处转移,广泛转移是致死的主要原因。

Granular cell tumor （GCT） in the digestive tract, rarely seen in clinical practice, is a neurogenic tumor of schwann cell origin and is mainly located in the submucosa. Often solitary, GCT grows slowly, with irregular shape. Microscopically, the tumor forms solid cluster of cells of round or polygonal shapes associated with few spindle cells. Immunohistochemistry shows S-100 proteins are present nearly in all cells within the tumor mass. The malignant features are often demonstrated as nuclear atypia. Most cases of GCT in the digestive tract have no clinical symptoms and are incidentally diagnosed upon gastrointestinal endoscopy examination for their nonspecific dyspeptic symptoms. The tumors are mostly confined to submucosa and appear as a yellowish or greyish white hemispherical nodule. The surface mucosa of the tumor is smooth and glossy. Multiple deep or big block biopsies from the nodule and from the surrounding mucosa are helpful for achieving correct diagnosis. Recently, endoscopic ultrasonography （EUS） has been used more frequently to determine the depth of tumor invasion in the digestive tract wall and may also be useful for evaluation of gastrointestinal submucosa tumors. The main criterion for diagnosing whether GCT is benign or malignant is distant organ metastasis or swollen lymph nodes. Surgically, GCT mass less than 2cm in diameter can be well removed endoscopically. The treatment for tumor inside muscular layer, malignant and recurrent GCT is wide local excision. Neither brachytherapy nor chemotherapy has been shown to be effective at present. The recurrence rate of malignant GCT in the digestive tract is very high following treatment at approximately 32%-59%, Distant metastasis may also be found. The main cause of death for GCT in the digestive tract is extensive metastasis.